Do you have another graphics card that you can try?
Do you still get the same ATI errors?
What do the Application Hangs refer to?
If you want more detailed errors you can do the following (although I'd guess that it will just reiterate the ATI).
Go to
start | search (type in)
.dmp
Note the location of your latest .dmp file.
Then:
1) Download and install the
Debugging Tools from Microsoft
2) Download and install this
debugwiz
3) Open the Wiz & Browse to, or paste in the path to, your latest .dmp file.
4) After the Wiz creates a Text document attach it back to this thread.